A GaN based semiconductor light-emitting device is provided. The light-emitting device includes a first GaN based compound semiconductor layer of an n-conductivity type; an active layer; a second GaN based compound semiconductor layer; an underlying layer composed of a GaN based compound semiconductor, the underlying layer being disposed between the first GaN based compound semiconductor layer and the active layer; and a superlattice layer composed of a GaN based compound semiconductor doped with a p-type dopant, the superlattice layer being disposed between the active layer and the second GaN based compound semiconductor layer.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A GaN based semiconductor light-emitting device comprising: a first GaN based compound semiconductor layer of an n-conductivity type; an active layer; a second GaN based compound semiconductor layer of a p-conductivity type; an underlying layer composed of a GaN based compound semiconductor including In, the underlying layer being disposed between the first GaN based compound semiconductor layer and the active layer, wherein the underlying layer has a thickness of 20 nm or more, and wherein the underlying layer is composed of a single composition and does not absorb light at an emission wavelength of the active layer; a lower spacer layer composed of an undoped GaN based compound semiconductor, the lower spacer layer having a thickness of 50 nm or less and being disposed between the active layer and the underlying layer, and a distance between the underlying layer and the active layer is 50 nm or less; and a superlattice layer composed of a GaN based compound semiconductor doped with a p-type dopant, the superlattice layer being disposed between the active layer and the second GaN based compound semiconductor layer, the superlattice layer having a structure in which a plurality of a first type of GaN based layers are stacked periodically and alternately with a plurality of a second type of GaN based layers.
2. The GaN based semiconductor light-emitting device according to claim 1 , further comprising: an upper spacer layer composed of an undoped GaN based compound semiconductor, the upper spacer layer being disposed between the active layer and the superlattice layer, the upper spacer layer configured to prevent a dopant of the second GaN based compound semiconductor layer from diffusing to the active layer; wherein the upper spacer layer has a thickness of 100 nm or less.
3. The GaN based semiconductor light-emitting device according to claim 1 , wherein the superlattice layer has a thickness of 5 nm or more.
4. The GaN based semiconductor light-emitting device according to claim 1 , wherein the superlattice of the superlattice layer has a period of two atomic layers to 20 nm.
5. The GaN based semiconductor light-emitting device according to claim 1 , wherein the superlattice layer has a p-type doping concentration ranging from 1×10 18 /cm 3 to 4×10 20 /cm 3 .
6. A GaN based semiconductor light-emitting device comprising: a first GaN based compound semiconductor layer of an n-conductivity type; an active layer; a second GaN based compound semiconductor layer of a p-conductivity type; an underlying layer composed of a GaN based compound semiconductor including In, the underlying layer being disposed between the first GaN based compound semiconductor layer and the active layer, wherein the underlying layer has a thickness of 20 nm or more, and wherein the underlying layer is composed of a single composition and does not absorb light at an emission wavelength of the active layer; and a lower spacer layer composed of an undoped GaN based compound semiconductor, the lower spacer layer having a thickness of 50 nm or less and being disposed between the active layer and the underlying layer, and a distance between the underlying layer and the active layer is 50 nm or less; wherein the second GaN based compound semiconductor layer has a superlattice having a structure in which a plurality of a first type of GaN based layers are stacked periodically and alternately with a plurality of a second type of GaN based layers.
7. The GaN based semiconductor light-emitting device according to claim 6 , further comprising: an upper spacer layer composed of an undoped GaN based compound semiconductor, the upper spacer layer being disposed between the active layer and the second GaN based compound semiconductor layer; wherein the upper spacer layer has a thickness of 100 nm or less.
8. The GaN based semiconductor light-emitting device according to claim 6 , wherein the second GaN based compound semiconductor layer has a thickness of 5 nm or more.
9. The GaN based semiconductor light-emitting device according to claim 6 , wherein the superlattice of the second GaN based compound semiconductor layer has a period of two atomic layers or more and a thickness per period of 20 nm or less.
10. The GaN based semiconductor light-emitting device according to claim 6 , wherein the second GaN based compound semiconductor layer has a p-type doping concentration ranging from about 1×10 18 cm 3 to about 4×10 20 /cm 3 .
11. The GaN based semiconductor light-emitting device according to claim 1 , wherein the underlying layer contains an n-type dopant and has an n-type doping concentration ranging from 1×10 16 /cm 3 to 1×10 21 /cm 3 .
12. The GaN based semiconductor light-emitting device according to claim 1 , wherein an emission wavelength λ, ranges from about 430 nm to about 480 nm.
13. The GaN based semiconductor light-emitting device according to claim 1 , wherein an emission wavelength λ, ranges from about 500 nm to about 550 nm.
14. The GaN based semiconductor light-emitting device according to claim 1 , wherein operating current density is 50 A/cm 2 or more.
15. The GaN based semiconductor light-emitting device according to claim 1 , wherein the underlying layer has a thickness of 50 nm or more.
16. The GaN based semiconductor light-emitting device according to claim 6 , wherein the underlying layer has a thickness of 50 nm or more.
17. The GaN based semiconductor light-emitting device according to claim 6 , wherein the lower spacer layer has a thickness of 20 nm or less.
18. The GaN based semiconductor light-emitting device according to claim 6 , wherein the lower spacer layer has a thickness of 20 nm or less.
19. The GaN based semiconductor light-emitting device according to claim 1 , wherein the underlying layer is Si-doped.
20. The GaN based semiconductor light-emitting device according to claim 6 , wherein the underlying layer is Si-doped.
21. The GaN based semiconductor light-emitting device according to claim 1 , wherein an upper spacer layer composed of an undoped GaN based compound semiconductor is formed directly on the active layer, and the superlattice layer is formed directly on the upper spacer layer, and wherein the upper spacer layer has a thickness of 100 nm or less.
22. The GaN based semiconductor light-emitting device according to claim 21 , wherein the upper spacer layer has a thickness of about 10 nm.
23. The GaN based semiconductor light-emitting device according to claim 1 , wherein a distance between the superlattice layer and the active layer is about 10 nm.
24. The GaN based semiconductor light-emitting device according to claim 1 , wherein the distance between the underlying layer and the active layer is about 20 nm or less.
25. The GaN based semiconductor light-emitting device according to claim 1 , wherein in the superlattice layer the first type GaN based layers have a thickness greater than a thickness of the second type GaN based layers.
26. The GaN based semiconductor light-emitting device according to claim 1 , wherein the superlattice layer has a structure in which a plurality of AlGaN layers each having a thickness of about 2.4 nm and a plurality of GaN layers each having a thickness of about 1.6 nm are stacked periodically and alternately.
27. The GaN based semiconductor light-emitting device according to claim 26 , wherein the superlattice layer includes five Al 0.15 Ga 0.85 N layers and five GaN layers stacked periodically and alternately.
28. The GaN based semiconductor light-emitting device according to claim 26 , wherein the superlattice layer has a thickness of about 20 nm.
29. The GaN based semiconductor light-emitting device according to claim 26 , wherein the AlGaN sublayers in the superlattice layer have an Al content ranging from about 0.1 to about 0.25.
30. The GaN based semiconductor light-emitting device according to claim 2 , wherein the upper spacer layer is formed directly on the superlattice layer.
31. The GaN based semiconductor light-emitting device according to claim 1 , wherein the active layer includes In, and the underlying layer has a lower In content than the active layer.
32. The GaN based semiconductor light-emitting device according to claim 1 , further comprising a contact layer formed directly on the second GaN based compound semiconductor layer.
33. The GaN based semiconductor light-emitting device according to claim 32 , wherein the contact layer is an InGaN layer with an In content of about 0.15 and having a thickness of about 5 nm.
34. The GaN based semiconductor light-emitting device according to claim 1 , wherein the lower spacer layer has a thickness of about 5 nm or less, and a distance between the underlying layer and the active layer is about 5 nm or less.
35. The GaN based semiconductor light-emitting device according to claim 1 , wherein the underlying layer is composed of a Si-doped InGaN based compound semiconductor.
36. The GaN based semiconductor light-emitting device according to claim 1 , wherein the underlying layer is composed of a Si-doped In 0.03 Ga 0.97 N based compound semiconductor.
37. The GaN based semiconductor light-emitting device according to claim 35 , wherein the active layer includes In.
38. The GaN based semiconductor light-emitting device according to claim 1 , wherein the underlying layer contains an n-type dopant and has an n-type doping concentration ranging from 2×10 17 /cm 3 to 2×10 19 /cm 3 .
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 29, 2009
March 31, 2015
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